Envelope opening apparatus and method

ABSTRACT

Envelopes are opened through frictional engagement and a resultant tension action along preweakened edges. An envelope is driven onto a moving belt and the envelope is detected in its path by a photocell. A time delay circuit allows the envelope to be moved to a predetermined station where shoes contact the envelope. The shoes move through an envelope plane intersecting path to frictionally engage the envelope only once. The shoe normal force in combination with the moving belt force cause the envelope to burst open at the preweakened edges after which it passes under a pair of rollers.

United States Patent 1 [111 3,739,543 Harris June 19, 1973 ENVELOPEOPENING APPARATUS AN METHOD Primary Examiner-Travis S. McGehee AssistantExaminer-John Sipos 75 I t: RlndG.H Hdd f'ld,N.J. nven or 0 8 a on 1eAttorney-Allan Ratner and Maleson, Klrnmelman & [73] Assignee: AutomatedMail Systems, Inc., Ratn Cherry Hill, NJ.

[22] Filed: June 21, 1971 [57} ABSTRACT [21] A L No; 154,827 Envelopesare opened through frictional engagement and a resultant tension actionalong preweakened edges. An envelope is driven onto a moving belt and[52] :LS. Cll. 53/3, 55/118312: the envelope is detected in its path bya photocell A [51] f 3 time delay circuit allows the envelope to bemoved to [58] 1e 0 care 5 a predetermined station where shoes contactthe enve- 225/]01 106 lope. The shoes move through an envelope planeintersecting path to frictionally engage the envelope only [56]References cued once. The shoe normal force in combination with theUNITED STATES PATENTS moving belt force cause the envelope to burst openat 3,060,075 10/1962 Kincaid 53/28 the preweakened edges after which itpasses under a 2,618,336 11/1952 Davidson pair of rollers. 3,529,7569/1970 Smith 225/100 34 Claims, 10 Drawing Figures PAIENIEB 9 SNEEI 1 BF5 IN VE' N T 0!? ROLAND 6. HARRIS WWmrrQawu/u ATTORNEYS PATENIEDJIINWE?!3.139.543

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SHEEI & 0f 5 IN VENTOR ROL A ND 6. HARRIS A TTOR/VEYS ENVELOPE OPENINGAPPARATUS AND METHOD BACKGROUND OF THE INVENTION A. Field of theInvention This invention pertains to the field of bursting machines. Inparticular, this invention relates to the field of preweakened envelopeopening apparatus to frictionally engage and open the envelope alongweakened edges.

B. Prior Art A number of apparatus and methods of opening preweakenedenvelopes are known in the art. However, most of the prior mechanismsrely on opening envelopes by cutting or burning the envelope edges or byengagement of the envelope between rollers operating at differentrotational speeds.

In those prior mechanisms which burst the envelopes by cutting a portionof one or more edges from the closed envelope, content placement hasbeen found to be a critical factor. These machines have been found to beinsensitive in distinguishing content edges from envelope edges with theresult that in some cases the contents have been destroyed.

Other apparatus provide for burning of envelope edges as the primaryfeature in the opening process; however, in these machines the envelopeburning rates are found to be critical in the process. In these cases,it has been found that where the contents lie contiguous to the burningedges, they also may be burned. Such mutilation of the contents cannotbe tolerated in instances where the contents include computer data cardsor other sensitive material.

Many of the prior mechanisms rely on opening the envelopes by engagementbetween rollers operating at different rotational speeds to provide atearing action on the weakened edges of the envelope. This does notprovide for different combined thickness of envelopes and contents whichoften leads to jamming of the envelopes between the rollers. In thesemachines, there is continued contact throughout the entire length of theenvelope during bursting. This tends to promote jamming and tearing ofthe panels in unwanted areas since continuing contact tends to produceunpredictable tearing forces. As a further deficiency, in most priormethods, the tearing forces were not applied only along the preweakenededge.

SUMMARY OF THE INVENTION A preweakened envelope has an upper and a lowerpanel and a force is applied within the plane of the envelope to thelower panel. In this manner, the lower panel is moved while the upperpanel is engaged through a force substantially normal to the envelopeplane. The combination of these forces is effective to burst open thepreweakened envelope.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top view of the envelopeopening appara tus;

FIG. 2 is an elevational view of the envelope opening apparatus;

FIG. 3 is a perspective view of a portion of the opening mechanismacting in conjunction with the path guidance mechanism;

FIG. 4 is a perspective illustration of a preweakened envelope usable inthe envelope opening apparatus;

FIG. 5 is an elevational view of the predetermined location of a heavystock envelope when contact is made by the opening mechanism;

FIG. 6 is an elevational view of the predetermined location of a lowweight stock envelope at initialization of contact by the openingmechanism;

FIGS. 7-9 are elevational views of the envelope taken sequentially afteropening and showing retraction of the opening mechanism; and,

FIG. 10 is a system block diagram detailing the actuation time delaycircuit for movement of the opening mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2,there is shown burst ing machine or envelope opening apparatus 10 forautomatically opening preweakened envelopes 12, shown in FIG. 4. Ingeneral operation, apparatus 10 provides for the application of a forceto envelope 12 on lower panel 14 or 16 coincident or tangent with theplane of envelope 12 in order to cause linear motion in a predetermineddirection. At a predetermined point in the travel direction, envelope 12upper pannel 14 or 16 is engaged with a force substantially normal tothe plane of envelope 12. The combination of normal and tangentialforces with respect to the envelope plane serves to burst openpreweakened envelope 12.

Although not part of the inventive concept as herein defined, adescription of envelope l2 follows in order to provide a clearunderstanding of apparatus 10 and the method steps employed in theopening operation. As shown, envelope 12 includes opposing panels orfaces 14 and 16 forming a closed internal volume body through attachmentat peripheral edges 18, 20, 22 and 24. Although either face 14 or 16 mayserve as the lower panel of envelope 12, for purposes of clarity thelower panel will be that face which is driven by a force substantiallyin the plane of motion of envelope 12 while the opposing face will bereferred to as the upper panel. Edges 18, 20 and 22 are provided withperforations, scoring, sanded or some like weakening means in order toachieve a weaker bond between faces 14 and 16 at these edges than isfound at peripheral edge 24. In a manner to. be discussed fully, machine10 engages envelope 12 in a particular manner to separate opposingpanels 14, 16 from each other along perforations 26, thereby openingenvelope l2 and exposing the contents contained therein.

Apparatus 10 structurally comprises frame or housing member 28, pathguidance or transporting mechanism 30, opening or contacting mechanism32, envelope detection means 34 and stacker 36. Housing 28 provides astationary platform attached to a base surface throughverticallyextending legs 38 shown in FIG. 2. Additionally, frame 28provides the necessary horizontal and vertical mounting walls permittingapparatus 10 to be an inclusively unitary structure where all majoropening mechanisms are affixed.

Envelope guidance or translating mechanism 30 transports envelope 12within a predetermined plane of motion defined by the upper surfaces 44,46 of a pair of endless belts 40, 42 shown in FIGS. 2 and 3. Guidancedrive motor 48 actuates pulley mechanism 50 where the combination isrigidly mounted to horizontal cross-bar 52, in turn secured to opposingvertically eX- tended legs 38. Pulley 54 is rotatably driven about anaxis substantially normal to the axis of rotation of motor 48 where therotation plane change is provided by a combination bevel/spur geararrangement or some like standard mechanism not important to theinventive concept.

Inclined drive belt 56 passes over and is driven by lower pulley 54 inorder to promote a rotational driving mechanism for pulley system 58.System 58 as is shown in FIG. 1 is rotatably mounted to vertical wallmember 60 of housing 28. Rotatable cylinder 62 of system 58 passestransverse to the longitudinal travel direction of envelope 12 when itis in linear motion on belts 40, 42. Transversely displaced belts 40, 42passing over cylinder 62 are frictionally driven by the correspondingrotation to provide a substantially horizontal planar movement forenvelopes 12 on upper surfaces 44, 46. It is therefore seen that inoperation, rotation of pulley 54 acting through belt 56 defines acorresponding coplanar rotation of pulley 64 which is rigidly mountedto, and commands a similar rotation of cylinder 62 which in turnprovides the basic driving mechanism for belts 40, 42.

As shown clearly in FIG. 2, each of belts 40, 42 have substantiallyidentical contour paths defined by driving cylinder 62, second drivencylinder 66 and tension rollers 68. Driving and driven cylinders 62, 66respectively are longitudinally displaced but are positioned verticallyin a manner so as to permit upper surfaces 44, 46 of belts 40, 42 to liein a substantially horizontal plane throughout the displacedlongitudinal distance. Driven cylinder 66 is rotatably attached to wall60 of housing 28 and is free to rotate about a transverse axis withrespect to the defined longitudinal direction. Freely rotating tensionrollers 68 are transversely attached to housing 28 on a lower surfacethereof to permit proper tensioning of belts 40, 42 on opposingcylinders 62, 66.

ln the manner described, path guidance mechanism 30 operates to providea transporting medium for envelopes 12 in a plane defined by uppersurfaces 44, 46 of belts 40, 42. Motor 48 actuation in combination withthe aforementioned pulley mechanism drives the upper surfaces of belts40, 42 in substantially linear motion. Envelopes 12 passing fromstacking apparatus 36 are deposited on surfaces 44, 46 with one ofopposing panels or faces 14 or 16 contiguous with surfaces 44, 46. Belts40, 42 are longitudinally moveable and frictionally grip panel 14 or 16thereby providing longitudinal path guidance for envelope 12 duringtravel through opening mechanism 32.

Opening mechanism 32 performs the envelope opening operation by moveablyengaging envelope 12 in a path which intersects the plane of movementdefined by upper surfaces 44, 46 of endless belts 40, 42. In operation,boots or shoes 72, 74 contact one of opposing panels 14 or 16 ofenvelope 12 as it is being guided in a longitudinal direction on belts40, 42. Shoes 72, 74 apply a force substantially normal to the envelopetravel path.

The normal force applied to upper panel 14 or 16 of envelope 12 isapplied for a small increment of time only once to produce a singularcontact for each of envelopes 12 being opened. This contact force isapplied by the impact of shoes 72, 74 to envelope 12 along substantialportions of opposing transverse edges 20, 22. Singular contact ofenvelopes 12 by shoes 72, 74 essentially produces a single impact onevery envelope at a predetermined point in the envelope traveldirection.

The panel of envelope l2 continguous with belts 40, 42 continues to havea frictional driving force applied coincident with the plane of motiondue to the movement of belts 40, 42. The combined normal andfrictionally horizontal forces provide frictional engagement of envelope12 at a predetermined station on upper surfaces 44, 46, the location ofwhich will be detailed in follow ing paragraphs. The continuouslongitudinal force provided to envelope 12 provides the necessary forceto disengage panels l4, 16 along scored or perforated edges 18, 20, 22.

In detail, opening mechanism 32 includes a pair of pivoting arms 76, 78transversely displaced with respect to each other on opposing belts 40,42. Arms 76, 78, shown clearly in FIG. 3, are pivoted about respectivepivoting rods 80, 82 which are rotationally journaled to vertical wallmember 60 of frame 28. Rotation of pivoting arms 76, 78 and consequentlyboots or shoes 72, 74 is, therefore, limited to a plane substantiallyperpendicular to the plane of motion of envelopes l2.

Tension spring 84, attached on opposing ends to pivoting arm 76 andtension member 86 respectively, provides a constant downward force onarm 76, as shown in FIG. 2. Tension member 86 provides a relativelystable platform being rigidly mounted to vertical wall member 60. Thecompressive force of spring 84 applied to arm 76 permits shoes 72, 74 tobe maintained in an open or displaced position with respect to surfaces44, 46. Since spring 84 and boots 72, 74 are longitudinally displacedfrom each other on opposing sides of pivoting rods 80, 82, a normallydownward force by spring 84 causes a resulting upward or disengagingdisplacement at a point where boots 72, 74 are located.

Transverse mounting bar 88 is rigidly secured through bolts 90 or somelike means to opposing pivoting arms 76, 78 as shown in FIG. 3. Shoes72, 74 are securely fastened to transverse mounting bar 88 throughmounting bolts 92. Vertical rod members 94 extend vertically at an upperend from mounting bar 88 to a pair of lower cylindrical disks 96 at thelower opposing ends. Rubber disks 98 are attached to lower cylindricaldisks 96 on each of boots 72, 74. Disks 98 provide a relativelyresilient engagement surface for envelope 12 when shoes 72, 74 areactuated to an engaging or contacting position.

Friction member 89 is rigidly attached to and vertically extending fromtransverse mounting bar 88. Member 89 is located substantially midwaywith respect to the transverse direction between endless belts 40, 42.The lowermost edge of friction member 89 is vertically displaced fromthe plane defining upper surfaces 44, 46 by an amount approximately l/32inch. By composition, member 89 is resilient in nature and constructedof a hardened rubber or some like material. Resilient friction member 89functions as an aid in folding back upper panel 14 or 16 as envelope l2longitudinally passes through the predetermined station on belts 40, 42.

Actuation of the path movement to an engaged position is provided bysolenoid mechanism 100 shown in FIG. 2. Mechanism 100 is structurallymounted to frame 28 of apparatus 10 in a fixed position. Moveable rod102 extends between solenoid 100 and pivoting point 101 of arm 76. Rod102 is rotationally mounted to arm 76 to permit a free upward anddownward path movement of boots 72, 74 when actuation takes place.

Actuation of solenoid 100 to a closed or engaged posi tion is dependenton envelope detection mechanism 34 in combination with a time delaycircuit to be described in following paragraphs.

In the manner described, spring 84 compressively holds boots 72, 74 inan open or non-touching displacement with respect to the plane uponwhich envelope 12 is longitudinally traveling. Upon detection ofenvelope 12 by detection mechanism 34, solenoid mechanism 100 actingthrough a time delay circuit pulls moveable rod 102 downward. Shoes orboots 72, 74 are directed in a curvilinear intersecting path withrespect to longi tudinally directed envelope 12. Disks 98 then contactone of opposing panels 14, 16. The singular momentary contact provides africtional force to be applied to envelope 12 and thus causes a rippingor tearing action along perforations 26.

Cantilever arms 104, shown in FIG. 3, are transversely aligned anddisplaced on belts 40, 42. Arms 104 comprise cantilever rods S rigidlysecured to frame 28 on one end and rotatably mounted to rollers 106 onan opposing end. Rollers 106 are provided to flatten envelope 12 to thebelt after engagement and opening by boots 72, 74 and to further preventa forward end of moved envelope 12 from curling in an upward direc*tion. In this manner, rollers 106 have the purpose of restraining openedenvelope 12 to a plane contiguous with belts 40, 42. As is seen, rollers106 are transversely displaced from each other to prevent blockage inretrieving envelopes in the event of improper opening of envelopes 12and possibly resultant jamming under shoes 72, 74 and rollers 106.However, in order to increase the structural integrity of cantileverarms 104 and associated rollers 106, a structural rod element may beconnected to opposing arms 104 transversely to present a unitarystructure. If such a structural member were added, it may be formed intoa transverse bridge to permit access to any envelopes 12 which havejammed under rollers 106. Under operating conditions, rollers 106maintain substantially rolling contact with opposing edges 20, 22 in anoverlapping manner.

Of importance, and shown clearly in FIGS. 1 and 3, disks 98 apply anengaging force on substantial portions of opposing transverse edges 20,22 of envelope 12. Disks 98 engage upper panel 14 or 16 in a transversediscontinuous manner within envelope 12 boundary edges. Although disks98 overlap edges 20, 22, contact is only made on upper panel 14 or 16since disks 98 are transversely tapered in an upward manner. Thetapering of disks 98 permits internal envelope boundary engagement, butdoes not permit additional engagement of moving belts 40, 42.

Contact made by disks 98 substantially near weakened edges 20, 22provides the largest tearing forces to be applied on perforations 26. Inaddition, where contact is not made on edges 20, 22, there is a possibletendency for upper panel 14 or 16 to form a transverse 22. The openingof envelope 12 in this way provides a smooth opening procedure toprevent any possible envelope jamming that may occur.

Platform roller 108 is attached to central shaft 110 which isrotatably'mounted to vertical wall members 60 on opposing transversesides. Roller 108 is positioned below and maintained substantiallycontiguous with the lower surfaces of belts 40, 42. Due to therotational capability of roller 108, the linear longitudinal movement ofbelts 40, 42 present a rolling contact relative drive to roller 108.Further, boots or shoes 72, 74 are vertically aligned with roller 108when in a closed or contacting position on belts 40, 42. Roller 108provides a relatively rigid platform upon which disks 98 may impingewhen contacting envelope 12.

Envelope detection mechanism 34 includes a standard photoelectric cell116 comprising light source 112 and appropriate circuitry shown in FIG.10. Emitter 112 is positioned vertically above the plane of longitudinaltransport for envelope 12. Emitter 112 generates a beam of light orelectromagnetic radiation continubridge or warping effect. This warpingmay culminate in eventual jamming of envelope 12 when passing from shoes72, 74 into rollers 106.

In order to provide a sequential tearing along perforations 26, it ispreferred that the land to sea ratio of ously through the longitudinalopening 114 between belts 40, 42. Detector 116 positioned below belts40, 42 is vertically aligned with emitter 112 to continuously receivethe emitted light beam. When envelope 12 passes longitudinally on uppersurfaces 44, 46 of belts 40, 42 and intersects the light beam, a timedelay circuit, shown in FIG. 10, electrically connected to the cell isactuated to operate solenoid in the manner previously described.

Once the leading edge of envelope 12 has interrupted the light signal,an electronic time delay is initiated which is variable substantiallybetween 0.001 to 0.5 seconds. This delay in solenoid 100 actuationpermits envelope 12 to longitudinally continue to a predeterminedstation before contacting boots 72, 74. The predetermined envelopestation may be defined as a positional transverse across belts 40, 42which is coincident with leading edge 18 at the time of contact of shoes72, 74 with upper panel 14 or 16. The station, therefore, defines thelongitudinal positioning of envelope 12 on belts 40, 42 at the timebursting contact occurs. Precise position control may be accomplished byadjusting a time delay control 154 located on vertical wall 60 of frame28. When this preset position in time is reached, a single shot pulse isdirected to solenoid 100, thus applying the downward force through boots72, 74 required to burst preweakened edges 18, 20, 22. The actuationtime delay circuit and associated flow diagram between detectionmechanism 34 and solenoid 100 is shown in FIG. 10 and is detailed in thefollowing paragraphs.

Interruption of the light signal between emitter 112 I and cell 116produces a signal from differential amplifier 146. The signal fromamplifier 146 sets first flip/- flop 148 thereby applying a pulse toone-shot or time delay circuit 150. The duration of the quasi-stablestate of circuit 150 may be adjusted by potentiometer 154 as well knownin the art. The signal from circuit 150 branches at nodal point 156 intotwo paths: (1) into amplifier 158 and counter 160 to count the number ofenvelopes 12 being opened and (2) into a path for actuation of solenoids100.

The signal passes through nodal point 162 and resets switch 148 as wellas being applied to flip/flop 164 which activates one-shot circuit 166.The pulse output signal from circuit 166 is applied through a pair of amplifier drivers 168, 170 which activate a pair of solenoids 100 to moveboots 72, 74 through a path intersecting the plane of envelope 12 onbelts 40, 42. Additionally, the signal recursively passes into secondflip/- flop 164 to provide reset for the next successive envelopeapplication.

Envelope stacker 36 provides an initial placement medium for preweakenedenvelopes 12 as well as a mechanism to insure singular displacement ofindividual envelopes 12 into path guidance mechanism 30. Stacker 36includes hopper 118 of standard construction being geometrically definedby inclined and longitudinally extended base surface 119 and normallydisplaced side walls or adjustable guide members 142. As shown in FIG.2, envelope stack 138 is initially maintained in substantially verticalalignment with respect to inclined base surface 119 before entry ontobelts 40, 42. In order to provide proper positioning during the openingprocess, envelopes 12 are stacked in hopper 118 having opposing panels14 or 16 contiguous each other with perforated edges 18 transverselyinterfacing with base surface 119.

Stacker drive motor 120 is rigidly mounted to crossbar 124 of frame 28.Motor 120 independently provides rotary drive actuation to stacker drivepulley 122.

Endless rotary belt 126 is frictionally driven by drive pulley 122 asshown in FIG. 2, passing over and frictionally engaging pulley 128 in anactuating drive mode of operation. Rotationally moveable transverse rod130 is fastened to, and driven by pulley 128. Rod 130, in turn, isconnected to rear transverse rod 134 through pulley belt system 132. Apair of rear disk members 136 which are rigidly secured to rear rod 134,contact envelope stack 138 on one panel 14 or 16 of individual envelopes12. Disks 136 are transversely displaced with respect to each other andcontact a forwardly positioned envelope 12 near edges 20, 22.Additionally, members 136 are located in fixed relation above basesurface 119 of hopper 118 to permit individual envelopes 12 to be movedunder and forward disks 136.

Clockwise rotation of disks 136 (as viewed in FIG. 2) bends a forwardlystacked envelope 12 under disks 136 and drives envelope 12 in a forwarddirection into contiguous contact with base surface 119. Resilientcylinder 140, rotationally driven by transverse rod 130 is positionedsubstantially mid-point the transverse direction of hopper 118. Cylinder140 releasably contacts an upper surface 14 or 16 of envelope 12 andprovides a longitudinal displacement to envelope 12 onto belts 40, 42.Adjustable guide members 142 may be adjustably moved on base surface 119to provide an adjustable wall guide path for envelope stack 138 beforecontact with disk members 136. Members 142, therefore, permit disks 136to contact individual envelopes 12 in substantially the same transversepositions thus providing a high degree of repeatability success duringthe opening operation.

In the manner described, envelope stack 138 within shoes 72, 74 duringthe opening operation. The time delay herein described allows envelope12 to continuously move on upper surfaces 44, 46 to the predeterminedstation necessary for proper bursting of edges 18, 20, 22. Properlongitudinal positioning is further complicated by the fact that thecontact station is not only a function of belts 40, 42 speed but is alsoa function of the stock of the envelope panel construction as well asthe contents contained therein. Where a lower weight stock envelope isused or the contents are flimsy such as scanning paper, it has beenfound that leading edge 18 should be contiguous with rollers 106 wheninitial contact by boots 72, 74 is made. In such a case, thepredetermined station is located under a leading edge of rollers 106.The contents and lower panel 14 or 16 are continually drivenlongitudinally under rollers 106, but the upper panel is restrained bythe force exerted b/ shoes 72, 74. As shown in FIGS. 6-9, the upperpanel may be nominally forced in a rearward direction due to thefrictional contact of disks 98 with the upper panel surface, thusresulting in a continuous flow of opened envelope 12 through rollers 106in a flattened condition. If the predetermined station defined initialcontact being made when edge 18 was substantially rearward of rollers106, the combined shoe forces and tangential belt forces would tend tocause edge 18 to move rearward before tearing occurs. Since edge 18 isstill constrained by the closed envelope 12 edges, the only freedom ofmotion is in an upward direction. This tends to curl envelope 12 out ofthe plane of belts 40, 42 which may cause a transverse crease on thestill closed envelope. The now creased envelope, no longer lyingcontiguous with belts 40, 42 may, therefore, jam under rollers 106 thusdisrupting the envelope opening operation. I

In order to provide a clearer understanding of the nature of thefrictional engagement and bursting action of the opening operation,FIGS. 6-9 present a sequential time action operation for the low stockweight envelope as hereinbefore described. As shown in FIG. 6, initialcontact is made by rubber disks 98 of shoes 72, 74 on upper panel 14when leading edge 18 has moved substantially under rollers 106. FIG. 7describes the initialization of the retraction process of shoes 72, 74after bursting has taken place wherein disks 98 remain in contact withpanel 14 to provide a continued rearward force thereby lifting panel 14away from face 16. It is also seen from FIG. 7 that rollers 106 flattenface 16 to prevent any curling action that may occur. Continuedretraction of shoes 72, 74 is shown in FIG. 8' wherein the curvilinearretraction path becomes apparent. The arcuate path travel in bothcontact and retraction phases is clearly shown to result from therestrained rotary motion of boots 72, 74 about pivoting rods 80, 82.This arcuate retraction does permit disks 98 to continue in frictionalcontact with surface 14 for an increased time interval, thereby ensuringa proper opening and passage under rollers 106. FIG. 9 illustrates thefinal phase in the opening of envelope 12 wherein disks 98 are retractedfrom contact with panel 14, and it passes under rollers 106.

Where a heavier stock envelope is used for paneling or where theinternal contents are more rigid such as is the case when the computercards are contained therein the time delay must be shortened. Theshortening of the actuation time delay results in initial contact asshown in FIG. 5. In this case, it is seen that disks 98 contact envelope12 at leading edge 18 and then sequentially follows the operationthrough substantially in the'same manner as described in FIGS. 7-9. Thecontact station for this type envelope 12 as shown, prevents any nickingof the internally placed card and allows lower panel 16 plus contents tomove smoothly under rollers 1116. The varying positional relation ofenvelope 12 with respect to shoes 72, 74 as a positional function oftime may be adjusted by changing the time delay as described in previousparagraphs. Empirically derived positions may further be accommodatedthrough analysis of the contents as well as envelope paper stock weightfor particular applications of the user.

Bursting machine or envelope opening apparatus 19 as herein describedpresents a machine permitting a vast increase in quality controlassociated with the opening of preweakened envelopes 12.

The method of opening preweakened envelopes 12 in broadest definition asherein described includes applying a force within the plane of envelope12 to lower panel 14 or 16 to move envelope 12 to a predeterminedstation on path guidance mechanism 30. At the predetermined station,opening mechanism 32 frictionally engages upper panel 14 or 16 through aforce substantially normal to the envelope plane. The force, applied bymechanism 30, in combination with the normal force generated by openingmechanism 32 provides a tearing of envelope 12 along perforations 26,thus opening the contents of envelope 12.

In the operating sequence of events, envelope stack 138 is insertedwithin stacker 36 with edges 18 contiguous to base surface 119 of theinclined plane as shown in FIG. 2. Individual envelopes 12 are removedfrom stack 138 by frictional contacting rear disk member 136. Envelopes12 are forced into a plane coincident with the plane defined by basesurface 119 and are fed into the substantially horizontal plane definedby endless belts or transporting means 40, 42 under frictionalengagement of resilient cylinder 140. Transversely displaced belts ortransporting means 40, 42 provide longitudinal aperture 114 spanned byenvelope 12 transverse to the direction of motion imparted by belts 40,42. Emitter and detector 112, 116 pass a continuous light beamvertically through aperture 114 and is interrupted by incursion offrontal edge 26 of envelope 12 into the continuous path. Interruption ofthe light beam initiates a time delay circuit to permit envelope edge 18to move into a predetermined station on upper surfaces 44, 46 beforecontact is made by opening mechanism 32 on panels 14 or 16. Thepredetermined station, as has been previously defined, is a transverseline on belts 41), 42 which leading edge 18 has reached when contact ismade by rubber disks 98. The station is adjustable in the longitudinalor direction of motion of envelope 12 to permit optimum positioning ofdifferent weight and stock envelopes l2 and contents. The positioningcontact station is clearly shown, for different envelope stocks, inFIGS. and 6. When envelope 12 has moved to the proper station, upperpanel 14 or 16 is engaged through a force substantially normal to theenvelope plane which bursts open envelope 12 along perforations 26. Theengagement by disks 98 includes a con tacting of panel 14 or 16 in asubstantially planar interface. Since disks 98 are separate entities,the contacting is, therefore, transversely discontinuous with respect tothe movement of envelope 12 in the longitudinal direction.

The engaging force applied by opening mechanism 32 through disks 98includes application over a substantial area of envelope 12. Shoes orboots 72, 74 are transversely positioned such that disks 98 move towardand in contact with envelope 12 to apply the engaging force oversubstantial portions of opposing transverse edges 20, 22 within thecontour boundaries of envelope 12. Since the lower surfaces of disks 98may overlap the envelope boundaries, it has been found preferable totaper disks 98 along a line substantially coincident with edges 20, 22in an upward and outward manner to avoid contacting both envelope 12 andbelts 40, 42 during the engagement step. Contacting by disks 98substantially near edges 20, 22 permits the largest tension forces to beapplied at the weakest envelope edges to allow a clean tear atperforations 26. In addition, where the contacting force is not appliedsubstantially on the preweakened edges, it has been found that atransverse warping may occur causing the envelope 12 upper panel to bearched in a transverse direction. Such warping or arching may then causejamming under rollers 106 thus disrupting the continued flow ofenvelopes.

Additionally, boots 72, 74 normally contact upper panel 14 or 16 for asmall increment of time when the envelope 12 has reached thepredetermined station thus producing singular contact as has beendescribed. As necessarily follows, engagement occurs during only aportion of the time that envelope 12 passes entirely through thestation. At no time for any envelope 12 will disks 98 touch the upperpanel 14 or 16 for the entire duration of the time the envelope 12passes through the station. The momentary contact reduces thepossibility of content mutilation due to continued contact of theenvelopes 12 by the impacting force which may cause content movementwithin the envelope and subsequent bending, warping or mutilation.

The bursting open of envelope 12 is followed by the step of flatteningenvelope 12 to maintain panels 14, 16 contiguous with belts 40, 42. Inthis final step, opened envelope 12 is engaged in rolling contact withtransversely displaced cantilever rollers 106. The roller heads extendacross edges 20, 22 to restrain warping or other undesirable effects andthus expose the contents of envelope 12.

In a modification of the invention, it may be preferred to accommodatevarying transverse length envelopes 12. To accomplish this adjustableenvelope length opening, transverse mounting bar 88 may haveincorporated therein a transverse slot having a width substantiallylarger than vertical rod members 94 but smaller than mounting bolts 92.A particular sized envelope 12 is measured, and bolts 92 are loosened topermit repositioning of boots 72, 74. Once located, bolts 92 aretightened and apparatus 10 has been reset to a new transverse envelopelength. In a similar manner, pivoting arms 78 may include a transversescrew arrangement, operated by an external handwheel,

which bears against shoes 72, 74 to provide the necessary transverseshoe moving force. Turning of the handwheel then transversely positionsshoes 72, 74 to the proper length. In this manner, shoes 72, 74 may bemanually or otherwise adjusted in the transverse direction to properlycontact varying size envelope panels 14 or 16.

What is claimed is: w

l. The method for opening a preweakened envelope having an upper andlower panel, including the steps of a. applying a force within the planeof said envelope to said lower panel thereof moving said lower panel,

b. engaging said upper panel of said envelope through a forcesubstantially normal to said envelope plane for bursting open saidpreweakened envelope and c. moving said upper panel about said lowerpanel until said upper panel lies in substantially the same plane assaid lower panel.

2. The method of claim 1 in which the engaging step includes applyingsaid normal force in a direction toward said envelope plane andfrictionally engaging said upper panel whereby said normal force incombination with said force within the envelope plane provides saidbursting open of said preweakened envelope along three edges thereof.

3. The method as recited in claim 1 wherein the step of applying a forceto said lower panel of said envelope includes the step of transportingsaid envelope to a predetermined station on a substantially planar pathfor said envelope.

4. The method as recited in claim 1 wherein the step of engaging saidupper panel includes engaging said upper panel in a substantially planarinterface.

5. The method as recited in claim 1 wherein the step of engaging saidupper panel includes engaging said upper panel in a transverselydiscontinuous manner with respect to said envelope movement.

6. The method as recited in claim 4 wherein the step of contacting saidupper panel includes the step of applying an engaging force onsubstantial portions of opposing transverse edges of said envelope.

7. The method as recited in claim 1 wherein the step of engaging saidupper panel of said envelope is immediately followed by the step offlattening said opened envelope to be coincident with said envelopeplane.

8. The method as recited in claim 7 wherein the step of flattening saidopened envelope comprises restraining by cantilevered rollers opposedtransverse edges of said envelope. g

9. Apparatus for opening a preweakened envelope comprising:

a. means for guiding said envelope in a predetermined plane, saidenvelope having a first panel contiguous to said guidance means,

b. opening means moveable in a path intersecting said predeterminedplane for contacting and frictionally engaging a second panel of saidenvelope for bursting open said preweakened envelope and moving saidsecond panel about said first panel, and I means for flattening saidsecond panel contiguous to said guidance means until said second panellies in substantially the same plane as said first panel.

10. The apparatus as recited in claim 9 including positioning means foractuating said opening means for contacting said second envelope panelwhen a leading edge of said envelope reaches a predetermined station onsaid guidance means.

11. The apparatus as recited in claim 10 wherein said predeterminedstation is located on a transverse line of said guidance means wherein aforward edge of said opening means path with respect to said envelopemovement, intersects said predetermined plane.

12. The apparatus as recited in claim 10 in which there is providedflattening roller means positioned forward of said opening means in thedirection of travel of said envelope and in which said predeterminedstation is located on a transverse line of said guidance means adjacentsaid roller means.

13. The apparatus as recited in claim 12 wherein said predeterminedstation for said envelope located adjacent said roller means isvertically positioned beneath said roller means.

14. The apparatus as recited in claim 9 wherein said opening meansincludes means for singularly engaging said envelope when said envelopereaches a predeter mined station, said engaging means for contactingsaid envelope during only a portion of the time of passage of saidenvelope through said predetermined station.

15. The apparatus as recited in claim 9 including roller means forflattening said opened envelope on said guidance means after saidopening means has contacted said second panel of said envelope, saidroller means positioned forward said opening means with respect to thedirection of travel of said envelope and contiguous to said guidancemeans.

16. A method for opening a preweakened envelope having an upper and alower panel including the steps of: I i

a. transporting said envelope in a predetermined direction with a planeof motion,

b. singularly engaging and contacting said envelope at a predeterminedstation during only a portion of the time that said envelope passesentirely through said station for bursting open said preweakenedenvelope and c. moving said upper panel about said lower panel untilsaid upper panel lies in substantially the same plane as said lowerpanel to form a single panel.

17. The method as recited in claim 16 wherein the step of transportingsaid envelope includes the step of moving said envelope to apredetermined station on an envelope guidance means through frictionalengagement between said guidance means and a lower panel of saidenvelope.

18. The method as recited in claim 16 wherein the step of engaging andcontacting said envelope includes the step of forming a frictionalrestraint for said envelope between an opening means moveable in a pathintersecting said envelope plane of motion to contact an upper panel ofsaid envelope and a path guidance means interfacing with a lower panelof said envelope.

19. The method as recited in claim 18 wherein the step of forming saidfrictional restraint includes the step of impacting said upper panel ofsaid envelope by said opening means with a substantially normal force22. The method as recited in claim 16 wherein the step of singularlyengaging and contacting said envelope includes the step of hitting saidenvelope on op posing transverse edges of said envelope.

23. The method as recited in claim 22 wherein the step of hitting saidenvelope includes the step of covering a substantial linear length ofsaid opposing transverse edges when said contact is made.

24. The method as recited in claim 16 wherein said engaging andcontacting step is followed by the step of maintaining said openedenvelope in planar contact with a path guidance means.

25. An apparatus for opening a preweakened envelope having a first andsecond panel comprising:

a. means for transporting said envelope in a predetermined direction,

b. opening means for contacting and frictionally engaging said secondpanel of said envelope in substantially planar contact, said engagementbeing transversely discontinuous with respect to said predetermineddirection, said opening means bursting open said envelope and movingsaid second panel about said first panel, and

means for flattening said second panel until said second panel lies insubstantially the same plane as said first panel.

26. The apparatus as recited in claim 25 wherein said contacting meansengages said envelope when a frontal edge of said envelope has moved toan adjustable predetermined station on said transporting means.

27. The apparatus as recited in claim 25 wherein said contacting meansis moveable in a path intersecting a plane of motion of said envelopefor contacting and frictionally engaging an upper panel of said envelopesubstantially simultaneous with, but not before said envelope reaches apredetermined station on said transporting means.

28. The apparatus as recited in claim 27 wherein said contacting meansengages said upper panel of said envelope through a force substantiallynormal to a plane of motion of said envelope defined by said motion ofsaid envelope in contact with said transporting means.

29. The apparatus as recited in claim 28 wherein said means forcontacting said envelope includes engage ment of said envelope upperpanel at said predetermined station during only a part of the time thatsaid envelope passes entirely through said station.

30. The apparatus as recited in claim 25 wherein said contacting meansengages said envelope on an upper panel thereof when said envelope hasmoved to a pre' determined station on said transporting means, saidcontacting means for engaging said envelope on substantial portions ofopposing transverse edges thereof.

31. An apparatus for opening a preweakened envelope having a first and asecond pane] comprising:

a. means for linearly translating said envelope in a predetermineddirection,

b. opening means for contacting and frictionally engaging said secondpanel of said envelope on substantial portions of opposing transverseedges of said envelope to burst open said preweakened envelope andmoving said second panel about said first panel, and

c. flattening said second panel until said second panel lies insubstantially the same plane as said first panel.

32. The apparatus as recited in. claim 29 wherein said contacting meansfrictionally engages said envelope on an upper panel thereof when saidenvelope has moved to a predetermined station on said translating means,said envelope having a lower panel being contiguous to said translatingmeans.

33. The apparatus as recited in claim 32 wherein said contacting meansengages said envelope in substantially planar contact, said engagementbeing transversely discontinuous with respect to said predetermineddirection. 1

34. The apparatus as recited in claim 31 including cantilever rollermeans positioned forward of said contacting means with respect to saidtranslating direction of said envelope, said cantilever roller means forflattening said opened envelope contiguous to said translating means.

1. The method for opening a preweakened envelope having an upper andlower panel, including the steps of a. applying a force within the planeof said envelope to said lower panel thereof moving said lower panel, b.engaging said upper panel of said envelope through a force substantiallynormal to said envelope plane for bursting open said preweakenedenvelope and c. moving said upper panel about said lower panel untilsaid upper panel lies in substantially the same plane as said lowerpanel.
 2. The method of claim 1 in which the engaging step includesapplying said normal force in a direction toward said envelope plane andfrictionally engaging said upper panel whereby said normal force incombination with said force within the envelope plane provides saidbursting open of said preweakened envelope along three edges thereof. 3.The method as recited in claim 1 wherein the step of applying a force tosaid lower panel of said envelope includes the step of transporting saidenvelope to a predetermined station on a substantially planar path forsaid envelope.
 4. The method as recited in claim 1 wherein the step ofengaging said upper panel includes engaging said upper panel in asubstantially planar interface.
 5. The method as recited in claim 1wherein the step of engaging said upper panel includes engaging saidupper panel in a transversely discontinuous manner with respect to saidenvelope movement.
 6. The method as recited in claim 4 wherein the stepof contacting said upper panel includes the step of applying an engagingforce on substantial portions of opposing transverse edges of saidenvelope.
 7. The method as recited in claim 1 wherein the step ofengaging said upper panel of said envelope is immediately followed bythe step of flattening said opened envelope to be coincident with saidenvelope plane.
 8. The method as recited in claim 7 wherein the step offlattening said opened envelope comprises restraining by cantileveredrollers opposed transverse edges of said envelope.
 9. Apparatus foropening a preweakened envelope comprising: a. means for guiding saidenvelope in a predetermined plane, said envelope having a first panelcontiguous to said guidance means, b. opening means moveable in a pathintersecting said predetermined plane for contacting and frictionallyengaging a second panel of said envelope for bursting open saidpreweakened envelope and moving said second panel about said firstpanel, and c. means for flattening said second panel contiguous to saidguidance means until said second panel lies in substantially the sameplane as said first panel.
 10. The apparatus as recited in claim 9including positioning means for actuating said opening means forcontacting said second envelope panel when a leading edge of saidenvelope reaches a predetermined station on said guidance means.
 11. Theapparatus as recited in claim 10 wherein said predetermined station islocated on a transverse line of said guidance means wherein a forwardedge of said opening means path with respect to said envelope movement,intersects said predetermined plane.
 12. The apparatus as recited inclaim 10 in which there is provided flattening roller means positionedforward of said opening means in the direction of travel of saidenvelope and in which said predetermined station is located on atransverse line of said guidance means adjacent said roller means. 13.The apparatus as recited in claim 12 wherein said predetermined stationfor said envelope located adjacent said roller means is verticallypositioned beneath said roller means.
 14. The apparatus as recited inclaim 9 wherein said opening means includes means for singularlyengaging said envelope when said envelope reaches a predeterminedstation, said engaging means for contacting said envelope during only aportion of the time of passage of said envelope through saidpredetermined station.
 15. The apparatus as recited in claim 9 includingroller means for flattening said opened envelope on said guidance meansafter said opening means has contacted said second panel of saidenvelope, said roller means positioned forward said opening means withrespect to the direction of travel of said envelope and contiguous tosaid guidance means.
 16. A method for opening a preweakened envelopehaving an upper and a lower panel including the steps of: a.transporting said envelope in a predetermined direction with a plane ofmotion, b. singularly engaging and contacting said envelope at apredetermined station during only a portion of the time that saidenvelope passes entirely through said station for bursting open saidpreweakened envelope and c. moving said upper panel about said lowerpanel until said upper panel lies in substantially the same Plane assaid lower panel to form a single panel.
 17. The method as recited inclaim 16 wherein the step of transporting said envelope includes thestep of moving said envelope to a predetermined station on an envelopeguidance means through frictional engagement between said guidance meansand a lower panel of said envelope.
 18. The method as recited in claim16 wherein the step of engaging and contacting said envelope includesthe step of forming a frictional restraint for said envelope between anopening means moveable in a path intersecting said envelope plane ofmotion to contact an upper panel of said envelope and a path guidancemeans interfacing with a lower panel of said envelope.
 19. The method asrecited in claim 18 wherein the step of forming said frictionalrestraint includes the step of impacting said upper panel of saidenvelope by said opening means with a substantially normal force withrespect to said plane of motion of said envelope.
 20. The method asrecited in claim 19 wherein the step of forming said frictionalrestraint includes the step of engaging said upper panel of saidenvelope in substantially planar contact, said contact being coincidentwith said plane of motion of said envelope.
 21. The method as recited inclaim 20 wherein the step of engaging said upper panel of said envelopeincludes the step of contacting said envelope discontinuously transversewith respect to said predetermined direction.
 22. The method as recitedin claim 16 wherein the step of singularly engaging and contacting saidenvelope includes the step of hitting said envelope on opposingtransverse edges of said envelope.
 23. The method as recited in claim 22wherein the step of hitting said envelope includes the step of coveringa substantial linear length of said opposing transverse edges when saidcontact is made.
 24. The method as recited in claim 16 wherein saidengaging and contacting step is followed by the step of maintaining saidopened envelope in planar contact with a path guidance means.
 25. Anapparatus for opening a preweakened envelope having a first and secondpanel comprising: a. means for transporting said envelope in apredetermined direction, b. opening means for contacting andfrictionally engaging said second panel of said envelope insubstantially planar contact, said engagement being transverselydiscontinuous with respect to said predetermined direction, said openingmeans bursting open said envelope and moving said second panel aboutsaid first panel, and c. means for flattening said second panel untilsaid second panel lies in substantially the same plane as said firstpanel.
 26. The apparatus as recited in claim 25 wherein said contactingmeans engages said envelope when a frontal edge of said envelope hasmoved to an adjustable predetermined station on said transporting means.27. The apparatus as recited in claim 25 wherein said contacting meansis moveable in a path intersecting a plane of motion of said envelopefor contacting and frictionally engaging an upper panel of said envelopesubstantially simultaneous with, but not before said envelope reaches apredetermined station on said transporting means.
 28. The apparatus asrecited in claim 27 wherein said contacting means engages said upperpanel of said envelope through a force substantially normal to a planeof motion of said envelope defined by said motion of said envelope incontact with said transporting means.
 29. The apparatus as recited inclaim 28 wherein said means for contacting said envelope includesengagement of said envelope upper panel at said predetermined stationduring only a part of the time that said envelope passes entirelythrough said station.
 30. The apparatus as recited in claim 25 whereinsaid contacting means engages said envelope on an upper panel thereofwhen said envelope has moved to a predetermined station on saidtransporting means, said contacting means for engaging said envelope onsubstantial porTions of opposing transverse edges thereof.
 31. Anapparatus for opening a preweakened envelope having a first and a secondpanel comprising: a. means for linearly translating said envelope in apredetermined direction, b. opening means for contacting andfrictionally engaging said second panel of said envelope on substantialportions of opposing transverse edges of said envelope to burst opensaid preweakened envelope and moving said second panel about said firstpanel, and c. flattening said second panel until said second panel liesin substantially the same plane as said first panel.
 32. The apparatusas recited in claim 29 wherein said contacting means frictionallyengages said envelope on an upper panel thereof when said envelope hasmoved to a predetermined station on said translating means, saidenvelope having a lower panel being contiguous to said translatingmeans.
 33. The apparatus as recited in claim 32 wherein said contactingmeans engages said envelope in substantially planar contact, saidengagement being transversely discontinuous with respect to saidpredetermined direction.
 34. The apparatus as recited in claim 31including cantilever roller means positioned forward of said contactingmeans with respect to said translating direction of said envelope, saidcantilever roller means for flattening said opened envelope contiguousto said translating means.